Does anybody remember this novel?
It was out in the late 1970's. Here's as much of the plot as I can remember.
A French detective is attempting to uncover a plot to assassinate the prime minister of France. In the process, he discovers that the PM is about to make a trip to Moscow to sign a treaty which would, essentially, surrender France to the Soviet Union. So, using an anti-aircraft missile that he somehow confiscates from some Arab terrorists, he shoots down the PM's plane.
Does this sound familiar?
Lynn, that's not it, that I know. Besides, it was Frederick Forsythe who wrote that story.